Piston packing for internal combustion engines



Sept. 13, 1932. L. c. MARSHALL 1,877,413

PISTON PACKING FOR INTERNAL COMBUSTION ENGINES.

Filed April 14, 1924 F|e.| Fla-.2

as I "s INVENTOR: LEWIS C. MAR'SHSALL.

.HIS'ATTYSL Patented Sept. 13, 1932 v UNFITEDISVT'VATES LAND, OHIO, A CORPORATION OF OHIO p rrsron racxmo r03 INTERNAL c ndemn ImGIivEs 71 l 1 Application filed April 14,

This invention pertains to metallic piston packing and more-particularlyto split ring packings of the, type employed in internal combustion engines.

Principal objects of the invention are to provide an improved packing of simple and durable type applicable to pistons of the usual 1 form employedin internal combustion en- 1 gines, such' pistons being of integral one-piece construction and provided with circumferential, packing grooves of fixed width and i substantially rectangular section; to provide a packing which without unusual difficulty or the employment of unusual tools may be installed in such piston grooves; and to provide a packing capable in an efiicient manner of preventinggas leakage or oil pumping even at extremely high rates of reciprocation but without imposing excessive frictional pressure upon the cylinderwalls.

' lVith the above objects in view, the present invention comprises in brief the provision of a unitary main ring which is inherently resilient in an axial direction and which is 1 adapted to bear. with resilient p'ressure againstthe side walls of the piston groove, together with a follower or expander ring for forcing the main ring outwardly against the cylinder wall. While the main ring is radially as well as axially resilient the follower ring, which may be of more resilient material, for example, tempered steel, isof utility in supplementing the inherent expansive force of themain ring and at the same time provides for breaking or covering the joint or split in the main ring. Furthermore, it is preferred although not essential, to provide the main and expander rings with co-operating engaging surfaces so constructed that a component of the expansive force of theexpander ring is directed axially to assistjthe main ringin maintaining its pressure/upon the side walls ofthe piston groove.

' In the accompanying drawing a preferred embodiment of the invention together with desirable modifications thereof is illustrated by way of example. a v j In the accompanying drawing, Fig. 1 is a perspective view of a piston packing embodying the ing length 1924. termini. me ger.

resent. "inve tion i its pre ferred form;

Fig. 2 is a fragmentary radial section showing the preferredpacking seated inthe, piston of an internal combus-- groove of the tion engine;

Figs. 3 to 9 inclusive sec- OF AMERICA, INC, '01 CLEVE:

ATE T 51 miwrs o. MARSHALL, tr mmers. mssacnosn'rrs, assrcmon, BY mam assren- I MENTS, TO THE smrrnx PISTON RING comumy tions similar to Fig."2,;but illustratingfriqdj;

fied embodiments of the invention;

Fig. 10 is afragmentary development of the main ring of the improved pa'ckin ,showing a modified arrangement ofthe ividing slot therein; I I I Fig. 11 is a viewsimilar to Fig. 10, show a further modified arrangementfof the dividing slot; and l l F g. 12 is a similar view, showing a further modified arrangement of th elsli'ts' in the ring,

together with another arrangement of the "dividing slot. a

Referring to the drawing,the numeral 1 designates the main packing ring and the numeral 2 the auxiliary or -expanderring.

The main ringl is provided 'with'a trans- 4 verse gap at the point 3' preferably in such-a manner as to 1 ring 2 is provided at thejpoint 4, the gaps in the two rings being staggeredin thej'usual manner. p v The main ring 1 is provided with plain "parallel radial surfaces and is of unitaryoorr struction consisting of a single'annular turn of uniform width which may be made in accordance with any of the usual methods used inmaking split piston rings; [This main ring is furnished with a plurality ofserie's of circumferentially extending slits, the slits of i one series being indicated bythenumera l fi and those of the other series by thegnumeral 6. The slits of the two series arearran ed in staggered relation-,ithesolid separat ng portionof the ring between adjacent slits' 'of eachseries being substantiallyfopposite. to'the center of a slit of the-opposite series with the result that the ring is elastic, *that'is'to say,

readily compressible and expansiblefiii an axial'directio'n. One'slit of oneiof the series, for ex'ample'the series 5, is preferably so arranged as to be substantially;bisected in by the gap 3 so that open ended slits of position relative to'each' other. 7

, of the groove.'

.expan'dthe main rin both in an dc t the'same construction as shown in Figs. 1

substantiall half the normal length extend oppositely rom the gap. The corresponding solid separating portion of the ring is also intersected by the gap. Thus when the ends of the ring are-brought together the slits andisolid separating portions extend in [of one piece: integral formation, and the acking grooves are turned in. the circumerential surface of the p'iston,.such grooveshaving substantially parallel plain side walls 9 and 10, which occupy a fixed and unvaryin In this, figure the main ring 1 is shownas seated in' the -piston groove 8, with its end faces bearing against the sidewalls 9- and 10 While the mainlringl inherently elastic, both in'an axialan in a radial direction,

it is found to be desirable tosupplement the elasticity of; the main ring by means of an auxiliary ring which may beofmore resilient material, such for example as tempered steel.- Inaccordancewith the simple structure arrangement illustrated in Figs. 1 and. 2, 'a single expander ring 2 provides the desired added elasticity for the main ring, both in an axial and also in a radial direction. The main ring 10 is furnished with a groovell symmetrically disposed in its innerpe'ripheral surface and preferably the opposite s de walls 12 and 13of'this groove are arranged in con-verging relationship. In the preferred'arrangement, these walls are "substantially fiat and converge towardthe outer surface of the ring, thespring expander. ring 2 being furnished withjcorrespondin inclined end faces which engage the sur aces 12 and 13of the main ring, thus tending to v I axial direction and in a radial irection. v Y

In the preferred arrangement, the ring 2 is of a thickness such that it seats wholly within the groove 11 of the main ring, so that the pistongroove 8 need not be of unusual n Fig.3 the main ring is of substantially and 2, but the auxiliary ring 14 is provided with acurved' surface bearing against the inclined walls 12 and 13 of the groove 11 of the main 'ring. This'form of expander ring is somewhat simpler to construct than that shown in Fig. 2, and maybe substituted therefor, if desired, the operation of the expander.

i 14 ng similar to that of' the expander In Fig. 4 a further modified arrangement is illustrated, the main ring 1 being slightly different from the ring 1 shown in the preceding figures, in that the bottom wall of its roove 11 is substantially parallel to its end ace, instead of being inclined. This bottom wall 15 co-operates with the radial end face of the auxiliary ring 16, the oppositeend face of said ring being inclined for engagemen't with'the inclined surface 12 of the main ring. This arrangement'functionsin substantially the same mannerv as those just previously described, although the axial component of the pressure of the expander ring may be somewhat less pronounced.

In Fi 5 a still further modification is shown w erein the mainring 1 is provided with a single inclined inner face 17 instead of the groove 11. A wire expander ring 18 bears against the surface 17 and tends to move the main ring radially outward and wall 9 ofthe piston vgroove. I

In Fig. 6 a further modification is illustrated, wherein the main ring 1 is of simple rectangular section having a plain cylindrical inner wall 19 which is engaged by a plain expander ring 20. In this arrangement the expander ring exerts no axial component of pressure against the main ring, the

"also to-compress saidring against the upper inherent elasticity of the latter'being depended u on for securingthe desired pressure agamst the side WllllS",Of the piston groove.

In Fig. 7 a still further modification is I shown in which themain ring l is furnished with a groove 21 of curved section in its inner peripheral surface for .the. receptionof a round expander rin 22. In this arrange ment as in that of I ig. 6 theexpander ring merely reacts in a radial direction against the main ring. j I

I In'Fig. 8 the main-ring 1 is furnished-with an undercut groove 23 in its outer face'for interlockingengagement with a bearing ring 24 adapted to engage the cylinder wall. A plain expander ring-25 bears against the inner faceof the main ring tending to expand the latter radially. In this arrangement the bearing ring 24 takes up the wear against the cylinder walland may readily be replaced without renewing the entire ring. I The bearmg ring 24 must necessarily have a clearance in the slot 23 to permit the proper compres sion'and expansion of the main ring 1.

Ill

In Fig. 9 a further modified arrangement I is shown inwhich th 'ai'n ringv l is'furnished with an undercut roove2in its inner wall, such groove having osit e con'verg ing end faces" 27 and 28 respt etivel'y'for engagement with inclined cnd'faces of an expander ring 29 having interlocking engagement with the groove 26. The operation of this modifiedform is substantially like ;'that shown in Fig. 2 except for the fact that the expander ring is interlocking withthe main ring so that the parts are not readily separated.

In Fig. 10 the main ring 1 is shown as provided with an inclined dividing slot 30 instead of the arrangement shown in Fig. 1.

In Fig. 11 the mainring 1 is shown as provided' with a dividing slot comprising the axial recesses 31 and 31 connected by the circumferential slot 32, the adjacent ends of both series of slits 5 and 6 being closed.

In Fig. 12 a further modified arrangement of the slits is shown in which the slits 5 and 6 are furnished with axially extending branches 5 and 6 respectively. This arrangement makes the ring extremely elastic and by providing a passage 33 into one of the slits, for example the slit 5, a ready means is provided for dividing the ring. t

The ring above described in any of its s ecific modifications is found to be big 11y efficient as a packing in preventing the leakage of gas and pumping of oil, even at the highest speeds of reciprocations-to which the piston may be subjected-"The packing thus provided is of simple form and can be-manufactured at relatively low cost, its partsdo not tend relatively to separate when. out of the piston groove and it requires no change in the shape or size of the piston groove usually furnished for its installation.

While certain specific modification of the invention are shown and described, it is to be understood that these are merely illustrative of the many modifications in which the broad invention may be embodied.

I claim 1. The combination with relatively reciprocating members, one of which has an annular groove therein, of a trans-split ring peripherally insertable in said groove, said ring being circumferentially slotted to form an axially flexible portion integrally connecting opposite side portions, and auxiliary resilient means reacting upon said side portions to hold' the same in sealing contact with the side walls of the groove and with a predetermined pressure limited to permit radial movement of the ring in the groove under working conditions.

2. The combination with relatively reciprocating members, one of which has an annuits lar groove therein, of a trans-split ring peripherally insertable in said groove, said ring being circumferentially slotted to form an axia 1y flexible portion integrally connecting opposite side portions, and. a radial expander reacting upon said opposite side pori tions of the ring to hold the same in sealing contact with the side walls of the groove and with a predetermined pressure limited to permit radial movement of the ring in the groove under workin conditions.

3. .The com ination with relatively reciprocating members one of which has an annuriphrally insertable in said groove, said ring being circumferentially slotted to form an axially flexible portion integrally connecting opposite side portions, and a resilient expander reacting upon said ring with a force having radial and axial components, the latter holding said opposite side portions in sealing contact with the side walls of the groove and with a predetermined pressure limited to permit radial movement of the ring in the groove under working conditions.

4. The .combination with relatively reciprocating members, one of which has an annular groove therein, of a trans-split ring peripherally insertable in said groove, said ring being circumferentially slotted to form an axially flexible portion integrally connecting opposite side portions and having a groove at its inner peripheral face and a resilient expander engaging the groove in said ring and reacting thereon with a force having radial and axial components, the latter holding said opposite side portions in sealing contact with the sides of the roove and with a predetermined pressure limited to permit radial movement of the ring in said groove under working conditions, said radial component coacting with the radial expansion of the ring to maintain peripheral sealing contact.

5. In a one-piece piston packing ring having an upper and lower series of staggered slots extending through the ring, said ring being thinner at the center line between its axial faces at the inside circumference of the ring and forming inner projecting circumferential edges, an inner-re-enforcing ring. 

